Floating point error and divergence detected

aannjj · July 2, 2013, 04:44

hi,
the simulation is of a large geometry having around 3 million mesh subparticles.I have divided the geometry into 8 volumes and there is now no error regarding that.
now in simulation in fluent..there is some problem..m quoting the error below..
i have set simulation to 15000 iterations..it is k-omega sst with default under-relaxed values.I am running parallel(8 processor) ..After about 5000 iterations it stops and gives this..
"turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 408811 cells
4076 2.5204e-07 2.5521e-08 2.3815e-08 2.3096e-08 1.4000e+00 3.8166e+16 21:33:40 10924

turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 902485 cells
4077 3.1344e+02 6.5344e-01 5.5458e-01 5.3253e+00 6.2227e-01 8.0000e-01 20:53:18 10923

turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1411997 cells
4078 2.9473e+09 1.7989e-01 3.8759e-02 4.5357e-01 3.6012e-01 8.0000e-01 22:10:12 10922

turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1558263 cells

reversed flow in 5158 faces on pressure-outlet 30.
4079 3.9124e+22 5.2860e-03 6.9058e-02 5.0526e-01 4.2653e-01 3.2658e+06 21:58:53 10921

turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1076961 cells

reversed flow in 5158 faces on pressure-outlet 30.
4080 1.0387e+28 4.7041e-03 7.9195e-02 5.9172e-01 3.1313e-01 2.1719e+04 21:49:49 10920

turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1210882 cells
4081 8.8677e+37 6.0362e+02 3.2125e+03 5.9525e-01 4.3557e-01 1.8990e+04 21:42:32 10919
# Divergence detected in AMG solver: omega -> Increasing relaxation sweeps!

turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1324638 cells

Divergence detected in AMG solver: omega
Divergence detected in AMG solver: omega
Divergence detected in AMG solver: omega
Divergence detected in AMG solver: omega
Divergence detected in AMG solver: omega
Divergence detected in AMG solver: omega
Divergence detected in AMG solver: omega
Divergence detected in AMG solver: omega
Primitive Error at Node 5: floating point exception

Primitive Error at Node 7: floating point exception

Primitive Error at Node 1: floating point exception

Primitive Error at Node 6: floating point exception

Primitive Error at Node 3: floating point exception

Primitive Error at Node 2: floating point exception

Primitive Error at Node 0: floating point exception

Primitive Error at Node 4: floating point exception"

what could be wrong??

July 2, 2013, 04:44	Floating point error and divergence detected	#1
aannjj New Member Charu Join Date: Jun 2013 Posts: 4 Rep Power: 13	hi, the simulation is of a large geometry having around 3 million mesh subparticles.I have divided the geometry into 8 volumes and there is now no error regarding that. now in simulation in fluent..there is some problem..m quoting the error below.. i have set simulation to 15000 iterations..it is k-omega sst with default under-relaxed values.I am running parallel(8 processor) ..After about 5000 iterations it stops and gives this.. "turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 408811 cells 4076 2.5204e-07 2.5521e-08 2.3815e-08 2.3096e-08 1.4000e+00 3.8166e+16 21:33:40 10924 turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 902485 cells 4077 3.1344e+02 6.5344e-01 5.5458e-01 5.3253e+00 6.2227e-01 8.0000e-01 20:53:18 10923 turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1411997 cells 4078 2.9473e+09 1.7989e-01 3.8759e-02 4.5357e-01 3.6012e-01 8.0000e-01 22:10:12 10922 turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1558263 cells reversed flow in 5158 faces on pressure-outlet 30. 4079 3.9124e+22 5.2860e-03 6.9058e-02 5.0526e-01 4.2653e-01 3.2658e+06 21:58:53 10921 turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1076961 cells reversed flow in 5158 faces on pressure-outlet 30. 4080 1.0387e+28 4.7041e-03 7.9195e-02 5.9172e-01 3.1313e-01 2.1719e+04 21:49:49 10920 turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1210882 cells 4081 8.8677e+37 6.0362e+02 3.2125e+03 5.9525e-01 4.3557e-01 1.8990e+04 21:42:32 10919 # Divergence detected in AMG solver: omega -> Increasing relaxation sweeps! turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 1324638 cells Divergence detected in AMG solver: omega Divergence detected in AMG solver: omega Divergence detected in AMG solver: omega Divergence detected in AMG solver: omega Divergence detected in AMG solver: omega Divergence detected in AMG solver: omega Divergence detected in AMG solver: omega Divergence detected in AMG solver: omega Primitive Error at Node 5: floating point exception Primitive Error at Node 7: floating point exception Primitive Error at Node 1: floating point exception Primitive Error at Node 6: floating point exception Primitive Error at Node 3: floating point exception Primitive Error at Node 2: floating point exception Primitive Error at Node 0: floating point exception Primitive Error at Node 4: floating point exception" what could be wrong??